I love the name Isabelle, but I didn't realise until recently that it derives from the name Elizabeth. I've always wanted to use the name Elizabeth, but thinking about a possible future sibset, would both names work well together or would it just sound silly?

Also, what are your thoughts on the different spellings of Isabelle/Isobel? Which do you prefer and why?

Isabel is the spelling I prefer. Isobel second, Isabelle is a little too frilly for me. Isabel and Elizabeth well I guess you could use them both. I've certainly heard of more similar names being paired together. Adrian and Adriana for b/g twins, for instance. This is not that similar. I would suggest using a different name, however.

I think the spelling Isabelle is gorgeous. The spelling is ultimately your personal preference as there as so many acceptable spellings.

While you could say that Elizabeth and Isabelle 'are basically the same name'. I think that could be a sweet tie between two sisters as Elizabeth and Isabelle actually look and sound completely different.

Yeah I love both the names, it's just a few people have said to me before that if I choose Elizabeth I shouldn't use Isabelle as 'it's like naming them the same name', but I've always thought as they're very different names despite having the same meaning and origin that I might be able to get away with it.
@anaxandra - I love IsabelleMorgan, but Morgan is a family name and I've always said I'd use it for Elisabeth. Great suggestions :) Claire is my auntie's name so can't use that. Juniper, Briony & Sunday are very cute names but not to my style. Beatrice is lovely but I don't really like it with Isabelle for some reason.
@grackym - nice nickname suggestions, I like Marie instead of Mary, but love its links with Mary as it was my grandmothers name so it's a nice thing to honour her. My cousin is Charlotte so that's not an option. Maeve and Nora are cute but not my style really.